Force transmitting intrauterine device

ABSTRACT

An intrauterine contraceptive device having substantial surface area for contact with the endometrium and capable of being releasably contracted to a size and shape for ready passage into the uterus and, when released, of expanding to conformably engage the walls of the uterine cavity in the mid-uterine area above the level of the internal so to resist expulsion, and thereafter of being readily removed, together with an introducer implement for releasably contracting the device in the proper orientation for insertion are disclosed.

I United States Patent 1191 1111 3,789,838 Fournier et al. Feb. 5, 1974[54] FORCE TRANSMITTING INTRAUTERINE 3,683,906 8/1972 Robinson 128/130DEVICE 2,484,449 10/1949 Fetterman 3,678,927 7/1972 Soichet 128/130 [76]Inventors: Erick-Pierre Fourmer, 30 Park Ave New York, N Y 001 FOREIGNPATENTS OR APPLICATIONS Alberto Lomeo, 200 E. End Ave., 9,546 7/1899Great Britain 24/252 PC w 10028 OTHER PUBLICATIONS Filed: 19, 1971 A. H.Robins Co. Advertising Booklet, Dalkon [211 App]. NO: 116,867 S3i7ed, A.H. Robins Co., Richmond, Va., Nov.

[52] US. Cl. 1.28/130 Primary Examiner Richard Gaudet [51] H ll. CI.A61f5/46 Assistant Examiner C M G [58] Field of Search 128/127-131, 261,Attorney, Agent, or Firm-Morgan, Finnegan, Durham 128/263, 260; 24/81,252 & Pine [56] References Cited 57 ABSTRACT UNITED STATES PATENTS 92990 2/197O C] k 28/130 An lntrautenne contraceptwe dev1ce havingsubstang'g H1972 g 1 28/1 30 tial surface area for contact with theendometrium and 4 10 1860 K1 capable of being releasably contracted to asize and 2,256,602 9/1941 Edwards 128/127 leased, 0f expandmgfoconformably engage the Walls 2,176,559 10 1939 M k i 12 130 of theuterine cavity 1n the mid-uterine area above the 3,537,445 1 l/ 1970Bumhill 128/ 130 level of the internal so to resist expulsion, andthereaf- ,0 ,879 1963 o h 8/ 130 ter of being readily removed, togetherwith an intro- 3,397,690 8/1968 1 l i i a i 128/130 ducer implement forreleasably contracting the device I gg in the proper orientation forinsertion are disclosed.

1 en 3,407,806 10/1968 Hulka et a1. 128/130 16 Claims, 47 DrawingFigures PATENTEU 51974 3.788.838

saw 1 OF 9 8 INVENTORS 7 I ERIcK-HERRE Founmen BY ALBERTO LOMEO 4 TTORNE Y3 PATENTEUFEB 5w 3.789.838

I sum 3 {IF 9 FIG. [5

FIG. [7 FIG. 18

INVENTORS 521cm PIERRE Iowa/wee BY 415mm 10/1450 PATENTEU 519743.789.838

SHEU Q of 9 cR0s5-$c r/o- PROFILE TYPES mp WEWS (TYPICAL) (rYPlc-Al.)

MOUNDS, CRATERS or Pmromr/o/vs W mm m and ale/0s CIRCLES, I 15! O 6STARS Q CROSSES J L and sou/mes A W PEAKS INVENTORS ERIcK-HERREYFOURNIER ny/ILBERTO oMEo F1623 fl FORCE TRANSMITTING INTRAUTERINEDEVICE BACKGROUND AND SUMMARY OF THE INVENTION Overpopulation presentssuch potentially disastrous socio-economic and ecological consequencesthat safe, effective, convenient and readily accessible means of curbingthe worlds birth rate other than through sterilization and abortion mustbe developed and massively implemented in the not-too-distant future.

Currently available modes of contraception fall broadly into threecategories. Physical and/or chemical barriers interposed between thesperm and the ovum such as condoms, diaphragms, spermicidal foams,creams and jellies. Hormonal interference with ovulation and/orimplantation of the fecundated ovum which can be either of the oral,injectable or implantable type. Intrauterine contraceptive deviceswhich, according to current theory, are believed to activate and toattract the presence of phagocytic cells through irritation of theendometrial cavity, thereby isolating the blastocyst and preventing itsimplantation, although the exact contraceptive mechanism involved hasyet to be fully understood.

All these methods have not been without varying forms and degrees ofdrawbacks. Let alone the fact that low incidence of pregnancy withcondoms, diaphragms and sperm-killing chemicals is heavily related tothe skill and care of the user, they are generally regarded as clumsyand inconvenient. Besides their relatively high cost, they require, inorder to be beneficial, a definite amount of sophistication andsustained individual motivation which inhibit their wide-spread usage,particularly among lower socio-economic groups.

Although rated the most effective to date, any hormonal treatmentdemands continuous periodic supervision by highly qualified medicalpersonnel for the assessment and evaluation of its systemic effects,which constitutes a definite limiting factor. In addition, they stillimply on the part of the user a measurable degree of self-discipline,particularly among highly mobile population groups resorting toone-a-day oral contraceptives.

In contrast to the other modes of contraception, the intrauterine deviceat least theoretically represents potentially the ideal method ofmasspopulation control for both developed and developing countries. Thiscontraceptive approach is basically inexpensive and convenient, andrequires a minimum of attention and supervision all of which militate infavor of its useeffectiveness. Furthermore, clinical experience withsuch devices has indicated the potential effectiveness and reliabilityof this approach to contraception without the need to alter naturalhormonal balances.

Any intrauterine contraceptive device, before it can expect to meet witha full measure of success, should ideally satisfy the followingobjectives:

The pregnancy rate should match or closely approach the low incidencelevel of hormonal contraceptives.

The rate of spontaneous expulsion should be very low.

Side effects such as pain, cramps, bleeding and other discomfort must beminimal so as to encourage the user to continue.

The design of the intrauterine device and of its introducer implement aswell as the insertion procedure, should be such that uterine perforationis made virtually'impossible during insertion of the device. a I i Thestructural design of the device should be such as to comfortably fit theuterine cavity of all women, especially nulligravidas.

The introduction of the device, as well as its removal,

should be painless, easy and relatively fast to perform by eitherphysicians or paramedical personnel after a short period of training.

The material composition of the device must be such that it causes noharm to the human body.

The device should be able to be mass produced at a low manufacturingcost.

Heretofore, this mode of contraception has not attained the level ofreliability and acceptance indicated by theoretical considerations, theavailable devices having been found lacking in one or more of theforegoing areas. The principal shortcoming has been in an inability tocontrol the rate of spontaneous expulsion with accompanying side effectssuch as painand bleedmg.

On the basis of the body of current clinical knowledge, therelationships between some of the physical characteristics of a deviceand its wanted and unwanted effects can be summarized in the followingtable where a plus sign indicates an increase as a direct function of aphysical factor, a minus sign a decrease and a zero no significantchange.

Pain Bleed- Resilience Stiffness Size Surface Contact RoughnessIrritation As can be observed, for instance, the rate of pregnancy andexpulsion is inversely proportional to the extent of surface contact ofthe device with the endometrial tissues, but with the disadvantage ofincreased bleeding; whereas a high degree of resilience and stiffnesstends to lower the expulsion rate while causing at the same time theunwanted effects of greater pain and bleeding. Similarly, too large asize in the dimensions of a device will lower the expulsion rate withouttoo much effect on the pregnancy rate while increasing bleeding and paindue to the distention caused to the uterine cavity.

Having in mind the foregoing, the present invention has as its generalobject the provision of an intrauterine contraceptive device whicheliminates the shortcom ings and drawbacks of the prior art. Moreparticularly, the invention has as its object the provision of a deviceand means for inserting same which embodies all of the objectives setforth above, especially one which couples low incidence of pregnancywith high resistance to spontaneous expulsion and ease of insertion andremoval.

Briefly and generally, the invention in its broad aspects comprises adevice having a substantially planar deformable but resilient bodycapable of being releasably contracted for ready passage in to theuterus and, when released, of expanding to conformably engage theuterine walls in the mid-uterine area substantially above the averagelevel of the internal os to resist expulsion. In accordance with a basicprinciple of the invention, the device has a substantially lobate outercontour including upper and lower pairs of structural uterine wallbearing lobes disposed in substantially symmetrical relation about alongitudinal axis extending therebetween with diagonally opposed upperand lower lobes of said lobe pairs directly coupled in contralateralforce transmitting relation by structural force transmitting meansextending in crossed relation diagonally across said axis, the devicebeing adapted for proper orientation in the uterus with its longitudinalaxis substantially coaxial with the cervical canal.

In one preferred form of the invention, the device has substantially theconfiguration of a figure 8, open at the top, the operative elementsincluding two substantially similar resilient S-shaped forcetransmitting members having upper and lower arcuate lobe formingsections and arranged in overlapped mirror-image relation with theirsaid arcuate sections outwardly disposed with respect to a symmetricalaxis longitudinally extending therebetween as aforesaid. In accordancewith a further principle of the invention, the terminal portions of thelower arcuate sections located nearest the cervical canal when thedevice is properly oriented in the uterus are resiliently joined viaspring-hinge means resiliently resisting inward compression of themembers towards the longitudinal axis, and externally accessiblewithdrawal means is provided for deactuating the springhinge means topermit the members to be readily contracted for removal.

In a preferred embodiment, the spring-hinge means comprises afilamentary extension of the force transmitting members having the formof an inverted-V expansion joint with an apex substantially coincidentwith the longitudinal axis, the withdrawal means comprising zones ofweakness formed at the junctions of the members with the V joint andfilament means affixed to the apex of the joint and readily externallyaccessible whereby the manual application of a force for removal of thedevice will result in the joint being inverted and a deactuation of itsspring energy normally resisting contraction of the force transmittingmembers towards the longitudinal axis.

In accordance with a further and preferred feature of the invention, thedevice is formed with a series of plastic membraneous regions which,still more preferably, incorporate minute regularly distributed surfaceprotuberances or asperities giving the device substantial surface areafor contact and surface irritation of the endometrium.

In accordance with still another aspect of the invention, the arcuatesections of the force transmitting members are provided on their outerwall bearing lobe surfaces with knurl forming protuberances for grippingthe uterine wall to provide stability and resistance to downwarddisplacement of the device.

Means in accordance with the invention for introducing the contraceptivedevice into the uterus comprises a shaft having handle means formed inone end and means formed in the other end having a bulbous searchinghead for releasably holding the device in a properly oriented contractedcondition, the shaft being formed with a curvilinear profileintermediate its ends having a double reverse curvature whereby thehandle section and holding section oppositely extend in axially offsetsubstantially parallel relation. This means for holding the devicecomprises a linear section of the shaft defining a cavity having abackwall and locating pin means operatively associated with the cavityfor cooperating with pin engaging means formed in the device whereby thedevice is releasably retained within the cavity with its longitudinalaxis parallel to the axis of the shaft and its force transmittingmembers contracted towards the longitudinal axis with their normallyfree ends held in fixed spatial relation.

Preferred dimensional and geometrical parameters in accordance with theinvention are that the outer wall bearing surfaces of the upper arcuatesections be normally spaced apart a substantially greater distance thanthe corresponding surfaces of the lower arcuate sections, that the forcetransmitting members cross over one another at substantially themid-point of the device taken along the longitudinal axis and that theyextend in relation to one another at an angle of about 030, and that thelowermost extremity of the device when positioned in the uterus liessubstantially above the average level of the internal 05, the devicebeing adapted to lie in the mid-uterine area.

Having summarized the invention, a detailed description follows withreference for illustrative purposes to the accompanying drawings whichform part of the specification, of which:

FIG. 1 is a diagrammatical view of the uterus illustrating its muscularstructure;

FIG. 2 is a diagrammatical view illustrating the muscular dynamics ofthe uterus including the two major centers of concentric forces;

FIG. 3 is a diagrammatical view of an intrauterine contraceptive deviceembodying the invention in its elemental concept illustrating sameunstressed within the uterine cavity;

FIGS. 4, 5 and 6 are diagrammatical views similar to FIG. 3 illustratingthe device conforming to the physiology of the uterine cavity undervarious contractive forces and the force transmitting and diffusingmechanism of the device to prevent expulsion;

FIG. 7 is a diagrammatical view similar to FIG. 3 illustrating thedevice conforming to the uterine cavity in the event that itaccidentally assumes an upsidedown position;

FIG. 8 is an elevational view, partially diagrammatical, of a preferredembodiment of the invention;

FIG. 9 is a cross-sectional view of the device of FIG. 8 taken alongline 9-9 thereof;

FIG. 10 is a cross-sectional view of the device of FIG. 8 taken alongline 10l0 thereof;

FIG. 10A is a cross-sectional view of the device illustrating analternate crosssectional configuration to that of FIG. 10;

FIG. 11 is a cross-sectional view of the device of FIG. 8 taken alongline l111 thereof;

FIG. 12 is a cross-sectional view of the device of FIG. 8 taken alongline l212 thereof;

FIG. 12A is a cross-sectional view illustrating an alternatecross-sectional configuration to that of FIG. 12;

FIG. 13 is a fragmentary cross-sectional view of the device taken inperspective at the cross-over region of the force transmitting membersof the device;

FIG. 14 is a diagrammatical elevational view illustrating in accordancewith the invention an alternate membranous configuration to that of FIG.8;

FIGS. 15-18 are fragmentary diagrammatical views illustrating, inaccordance with the invention, four alternate lobate knurlconfigurations for the arcuate sections of the device;

FIG. 19 is a chart illustrating various possible membrane asperityconfigurations in accordance with the invention;

FIGS. 20-23 are diagrammatical elevational views illustrating acontraceptive device in accordance with the invention being removed fromthe uterine cavity;

FIG. 24 is an elevational view of an introducer implement in accordancewith the invention releasably holding a contraceptive device similar tothat of FIG. 8;

FIG. 25 is a top plan view of the introducer and device combination ofFIG. 24;

FIG. 26 is a diagrammatical elevational view illustrating the techniquefor inserting a contraceptive device utilizing the introducer implementof FIG. 24;

FIG. 27 is a sectional view taken transversely of the uterine cavityillustrating the contraceptive device held in its contracted state bythe introducer as in FIG. 26 and further illustrating the manner bywhich the device is disengaged;

FIG. 28 is a view similar to FIG. 27 illustrating the contraceptivedevice fully expanded after disengagement from the introducerconformably engaging the walls of the uterine cavity;

FIGS. 29, 30 and 31 are enlarged side and end elevational and bottomplan views, respectively, of the contraceptive device and introducercombination of FIG. 24;

FIGS. 32, 33 and 34 are views similar to FIGS. 29, 30 and 31,respectively, illustrating an introducer implement of alternateconstruction in accordance with the invention releasably holding acontraceptive device similar to that of FIG. 8;

FIGS. 35-37 are diagrammatical views of three alternate introducerlocating pin configurations in accordance with the invention forreleasably engaging a contraceptive device as herein illustrated.

FIGS. 38, 39 and 40 are views similar to FIGS. 29, 30 and 31,respectively, illustrating still another alternate introducerconstruction in accordance with the invention releasably holding acontraceptive device similar to that of FIG. 8;

FIGS. 41, 42 and 43 are views similar to FIGS. 29, 30 and 31,respectively, illustrating in combination with a contraceptive device asherein illustrated yet another introducer construction in accordancewith the invention;

FIG. 44 is an enlarged top plan view of the contraceptive device andintroducer combination of FIG. 41;

FIG. 45 is a fragmentary diagrammatical view of a contraceptive devicein accordance with the invention having alternate pin engaging locationsto that of FIG. 8 for use with the introducers of FIGS. 32, 38 and 41;and

FIG. 46 is a perspective view of an intrauterine con traceptive deviceand introducer combination in accordance with the invention prepackagedfor use.

Turning now to the drawings in detail wherein like reference charactersare employed to designate like parts throughout, an intrauterine deviceembodying the invention in its elemental concept is illustrateddiagrammatically in FIG. 3, the device being shown in unstressedcondition within the uterine cavity.

In accordance with the invention, the device comprises a substantiallyfilamentary compressible resilient body having a longitudinal axis SSwhich extends substantially coaxially with the cervical canal when thedevice is properly positioned within the uterine cavity as shown in FIG.3. The operative elements of the illustrative embodiment include twosubstantially similar S-shaped resilient force transmitting members 50and 51 having upper arcuate arm sections 52 and 53, respectively, andlower arcuate arm sections 54 and 55, respectively, members 50 and 51being disposed in overlapped mirror-image relation with respect to thelongitudinal axis SS to form a substantially planar body. The lowerarcuate arm sections 54 and 55 at their terminal portions are joined viaspring-hinge means 57 whereas the terminal portions of the upper arcuatearm sections 52 and 53 are normally disposed in overhanging spaced apartmovable relation, as shown. The force transmitting members crossintermediate their upper and lower arcuate sections at a point 56substantially coinciding with axis SS.

The configuration of the device thus defined when unstressed can be seento markedly resemble the contour of a numeral 8, unclosed at the top,whose overlapping members 50, 51 intersect almost tangentially and arefree to slide past one another in any direction and to independentlywithstand deformations due to their plasticity. The overhanging terminalportions of arms 50 and 51 are normally spaced apart as shown when thedevice is unstressed and curve slightly inwardly toward the open centerof the upper section of the device away from the sensitive zones of thecornua.

The outer contour of the device can be characterized as having upper andlower pairs of wall bearing lobes formed by the arcuate sections of theforce transmitting arms 50, 51 which are laterally disposed insymmetrical relation with respect to axis SS to define two transverseaxes T-T and MM. The cross-bar sections of the arms 50, 51 serve tointerconnect in force transmitting relation diagonally opposed upper andlower lobes to provide contralateral transmission and diffusion of theforces exerted on the lobe regions by the uterine walls.

The spring-hinge means 57 preferably comprises a filamentary extensionof the force transmitting members 50, 51 having the form of an invertedV expansion joint having an apex substantially coincident with axis SS,as illustrated. The spring-hinge joint serves, in accordance with theinvention, as the source of spring energy to the force transmittingmembers 50, 51 resiliently resisting compression of the members towardsthe longitudinal axis S--S when under stress of uterine contractions.The ability of the device to resist contraction under such conditions isan important feature of the invention as will hereinafter more fullyappear.

In accordance with a further feature of the invention, the device isprovided with withdrawal means for deactuating the spring-hinge joint 57to permit the device to be contracted towards its longitudinal axis SSin order to facilitate withdrawal. As presently illustrated, thewithdrawal means comprises zones of weakness 58 and 59 (See FIG. 8)formed in the filamentary structure at the junctions of the members 50and 51 with the base of joint 57, and a monofilament 60 affixed to theapex of joint 57 by suitable means such as by ring 61. By simply pullingwith sufficient force on filament 60, which is adapted to be externallyaccessible through the cervical canal, the zones of weakness can besufficiently stressed, as lower arcuate lobe forming sections 54, 55press against the uterine walls, to cause joint 57 to invert therebylosing its spring energy and permitting the device to be readilycontracted.

Dimensions for parous cavities should preferably not exceed 25millimeters when the device is unstressed along its longitudinal axis SSand 24 millimeters at its upper major transverse axis TT. (See FIG. 8)More preferably, the geometry of the device should obey a number ofconstant ratios for optimal results. The spacing between upper arcuatearm sections 52 and 53 should be substantially greater and ideally onthe order of l /2 times greater than the spacing between lower arcuatesections 54 and 55, while the overlapping force transmitting arms shouldcross at substantially the midpoint of the device when measured alonglongitudinal axis SS. In addition, the angle between the tangents takenon the two intersecting arms 50 and 51 at the point of intersection 56denoted as angle a in FIG. 3 should preferably not exceed 30.

The importance of these dimensional parameters can best be understood inlight of the theoretical considerations underlying the invention and themanner in which the device reacts to intrauterine contractions to avoidspontaneous expulsion.

The muscular structure of the uterus follows the configuration of itspear-like shape. As diagrammatically represented in FIG. 1, theconcentric pattern of crosslaid muscular fibers assumes from the top tothe midsection of the uterus a direction generally inclined at a 45angle. From the mid-section down to the isthmus, the inclination of themuscular fibers becomes progressively less angulated to a point wherethe muscles form horizontal rings from the level of the isthmus down tothe cervix.

Thus, the muscular dynamics of the uterus can be reduced for practicalpurposes to two major centers of concentric forces as shown in theplanar representation of FIG. 2:

first, two cross-lines of forces intersecting at a 90 angle andextending from the cornua down to about the mid-portion of the uterus,and

second, a series of minor lines of forces generated by the ring musclesencircling the cervial canal.

However, the uterine muscular structure is so dense that it can produceon stimulation an almost infinite variety of deformations of the uterinecavity. Taking into consideration the classic segments of the uterus,contractions can originate at three levels: at the level of the fundusin one or both cornua regions, at the miduterus, or at the isthmus whichfor practical and functional reasons will hereinafter be referred to asthe area of the internal os.

Contractions starting in a circular fashion at the level of one of thecornua regions will cause distortion of the cavity with a resultingcontralateral and diagonally downward displacement of any uterinecontent. A bilateral or in toto fundal contraction will produce with orwithout dilation of the uterine mid-portion or of the internal s area, aremarkable reduction in size of the volume of the uterine cavity placedjust above and just below the tubal insertion with the displacement ofany uterine content almost vertically downward. A separate, almosthorizontal contraction at the mid-portion of the uterus will tend todeform the cavity in the shape of an hour-glass acting as an ejectingforce against any uterine content that offers resistance at that level.A contraction at the level of the internal 0s and, for that matter, atthe level of the isthmus, can produce a dual effect: a restrictivedistortion of the lower part of the uterus and, possibly simultaneously,a widening in the diameter of the internal 05 with a resultant downwardejection reaction.

In any event, the essential aspect to consider is that these variousforms of contractions seem to originate chiefly at the level of thecornua and in the particularly sensitive area of the internal 05.Considering further that the volumetric dimensions of the uterine cavityare far from being static but vary with the different phases of themenstrual cycle, we are led to believe that any intrauterine deviceprimarily designed to exert pressure on the periphery of the uterinecavity or to resist cornpression from the uterine walls in order toresist expulsion is unphysiological. In addition, the foregoing suggeststhat the configuration of any such device should be such as to avoidstimulating the sensitive contraction triggering points of the cornuaand of the internal os by evading contact with these areas as much ascan practicably be done.

In accordance with the invention, prevention of expulsion isaccomplished in three separate ways: minimal contact of the device withuterine walls, compressibility of the device, and contralateraltransmission and diffusion of uterine contraction forces.

The size of the device is not intended to cover the entire periphery ofthe uterine cavity, least of it the area of the internal os, whereunwanted stimulations associated with pain and bleeding wouldnecessarily be generated. Rather, the device is designed to fit in themiddle section of the uterine cavity where fecundated ova tend toimplant themselves most frequently and to stay away from the contractiontriggering zones of the cornua, the area of the internal os and theextreme lateral ends of the uterine cavity.

To that effect, the curvature of the overhanging terminal portions ofarms 50 and 51 is smooth and oriented inward, away from both cornua: the24 millime ter width of the device along its major transverse axis TTcan be comfortably accommodated by most uterine cavities whose averagewidth from cornu to cornu is in the extremity of 33 millimeters whilethe lowermost extremtity of the device lies at least 10 millimeterssubstantially above the average level of the internal os.

In the event of minor uterine contractions, the device first acts like acushioning spring and absorbs the initial shock from the uterine wallsat its four lobate regions defined by the transverse axes TT and M--M.Contraction forces may then cause the device to constrict and to adaptitself to the restricted dimensions of the uterine cavity, particularlyin its uppermost transverse plane where the upper overhanging arcuatesections 52, 53 can simultaneously fold inward toward the open center ofthe device and overlap each other, depending upon the direction of thecontractions (See FIG. 4).

As a whole, the structural design of the device is such that itsoriginal geometry can ultimately withstand a total size reduction in theorder of 40 percent and spring back to its normal shape once uterinecontractions cease. In accordance with the principles enunciated above,this device is primarily designed not to fight against the physiology ofthe uterus but to conform to it.

In case of strong contractions, as can happen during menstruation, thedevice utilizing uterine muscular forces will anchor itself against thewalls of the uterine cavity in order to keep from being expelled. Theanchoring effect is achieved through the cross-bar relationship of theforce transmitting arms 50, 51 whereby the multi-directional forcesexerted by the uterine walls against one or both sides of the device aretransmitted and diffused contralaterally to the opposite sides.

Referring to FIGS. 4-7 inclusive to illustrate, a bilateral contractionexerted at the level of the fundus causes the upper arcuate sections 52and 53 to be compressed inwardly with the forces being transmittedcontralaterally to the lower diagonally opposed arcuate sections 54 and55 respectively, as shown in FIG. 5. As a result, the lower arcuatesections 54 and 55 bulge outwardly resisting downward displacementtoward the area of the internal os. Should the contractions occur at themid-section of the uterus, the reverse occurs: sections 54 and 55 arecompressed inwardly while their corresponding diagonally opposed arcuatesections 52 and 53 expand and anchor themselves in the upper part of theuterine cavity. Muscular forces generated by a partial contraction atthe level of the fundus and acting unilaterally on the upper arcuatesection 52 of arm 50 (See FIG. 6) are entirely directed toward lowerarcuate section 54 of arm 50 causing the device to deform and tilt onits longitudinal axis 8-8 and to subsequently diffuse some of the forcesto arm 51 whose upper aruate section 53 tends to anchor itself up withan ascending motion. In the remote event that the uterine contractionsforce the device in an upside-down position as shown in FIG. 7, thestructural design is such that the cross-bar mechanism can still operateeffectively and prevent the device from engaging into the area of theinternal as well as from being expelled.

In order to increase the adherence and anchoring ability of the deviceagainst the uterine walls, minute knurl-forming protuberances such ashereinafter described can be formed in the outer lobate wall bearingsurfaces of the four arcuate sections of the device.

On the basis of the foregoing, the importance of the interaction betweenthe shape and the dimensions of the device can be appreciated: thespring-hinge joint 57 acts as a fulcrum permitting each forcetransmitting member to react independently whereby forces are dif fusedto the points of least resistance through the device. In turn, thisspring-hinge mechanism constitutes an important complement to thecross-bar mechanism of the members, the effectiveness of which isdirectly related to the amount of built-in leverage available.

In order that the force transmitting arms 50 and 51 can developsufficient torque to properly transmit and direct forces against theuterine walls, the dimensional and geometric parameters hereinabovedescribed should be followed.

It is to be appreciated that the invention in its broad aspects is notlimited to the figure 8 configuration herein illustrated and described,but the cross-bar mechanism and its advantages can be achieved inaccordance with the invention by any other suitable configuration andorientation.

A preferred embodiment of the invention is illustrated in FIGS. 8-12. Inthe preferred form illustrated, the plastic body of the device comprisesa substantially filamentary structural frame 62 describing the basicgeometrical configuration illustrated in FIG. 3 and constituting theareas of maximum cross-section of the device, and membrane means isintegrally formed with the frame to provide substantial surface contactwith the endometrium.

While the cross-section of the frame 62 varies according to the specificfunctions to be performed by its various segments, in general, thecross-section is preferably ovoid having a major axis in the plane ofthe device which is greatest at the overlapping sections of the members50, 51.

Since the main function of the cross-bar mechanism of members and 51 isto transmit contraction forces, the major cross-sectional axis of theframe is at its greatest in this region to provide structural strength.In order to keep the bulk of the device down as much as possible toavoid bleeding and discomfort, the frame in this region is alsosubstantially flattened. (See FIGS. 9 and 13) Moving upwardly towardsthe terminal portions of upper arcuate sections 52, 53 where flexibilityis required, the shape of the frame gradually takes on a more roundedcross-section and the major crosssectional axis lying in the plane ofthe device undergoes a progressive diminution (See FIGS. 10 and 11).Similarly, the frame progressively regains an ovoidal section andundergoes a slight reduction in its major axis in the lower arcuatesections 54, 55 in a direction towards their terminal portions (See FIG.12). At junctions 58 and 59 at the base of spring-hinge joint 57, theframe illustratively undergoes a major decrease in section to form zonesof weakness so that the joint can be readily inverted prior to removalof the device as will hereinafter be described. The optimumcross-sectional shape and dimensions of the frame can be determinedthrough use, as will also be the case with the geometrical parameters ofthe inverted-V joint 57.

An important feature of the invention resides in the provision ofplastic inwardly deformable membranous regions which are strategicallylocated so as to maximize Contact with the endometrium withoutinterfering with the dynamic mechanism and flexural ability of thedevice and without creating sources of pain and bleeding.

It hasbeen empirically verified that the extent of surface contact withthe endometrium is directly related to low pregnancy rate. At this stateof the art, the exact contraceptive process involved is still a matterof conjecture but, on the basis of recent investigations, the mostprobable reason appears to be the accumulation of macrophages around thesurfaces of the device. Thus, the greater the endometrial area covered,the larger the accumulation of macrophages and the lower the probabilityof conception. In order tomaximize their effectiveness, thisaccumulation of macrophages should preferably be made to occur at thelevel of the fundus as well as in the mid-uterine area whereinimplantation takes place most frequently.

To that end, the body of the device is preferably formed as illustratedin FIG. 8 with thin pliable plastic membrane-like regions operativelyassociated with the structural frame at the overhanging terminalportions of the upper arcuate sections 52 and 53, at their midsectionsin the region of overlap and at their lower arcuate sections 54 and 55.

Referring specifically to FIG. 8, a pair of elliptically shapedmembranous regions 63 and 64 extend inwardly from the overhangingterminal portions of upper arcuate sections 52 and 53 where they arefree to bend downwardly toward the open center of the device in theevent of fundal contractions. The membranous re- .gions 63 and 64 areformed with two similarly located pin engaging openings 65 and 66respectively which can be reinforced as shown. Openings 65 and 66comprise the means in conjunction with ring 61 at the apex of joint 57by which the device is releasably secured in a contracted state onto asuitable introducer implement for and during insertion into the uterus,all of which is hereinafter described.

FIGS. and 10A illustrate two possible crosssectional forms thatmembranous regions 63, 64 can take. In FIG. 10, the membrane structureis substantially uniform in cross-section from a narrowed neck 67 at itsjunction with frome 62 to its free edge. Alternatively, FIG. 10A shows amembrane section which gradually diminishes in thickness. In any event,the membrane regions should be formed so that they do not interfere withthe ability of the upper arcuate arm sections to flex downwardly underfundal contractions.

Referring .to FIG. 8 and FIG. 13, a second set of membranous areas 68and 69 illustratively extend from the opposite sides of member 51substantially above and below its region of overlap with the oppositemember 50. Upper membrane area 68 extends from the inner surface ofupper arcuate arm section 53 substantially at the transverse axis TT andgradually increases in width as it approximates the curvature of theframe until it reaches the overlapping cross-bar region where it is at amaximum, and then tapers down until its point of termination on theouter surface of lower arcuate section 55 somewhat above transverse axisM1-M. Lower membrane area 69, which extends in the opposite direction tomembrane area 68, has a similar tapered configuration as it follows thecontour of the frame from the outer surface of upper arcuate section 53to traverse substantially the entire inner extent of lower arcuatesection 55 terminating close to springhinge joint 57.

FIGS. 9 and 13 illustrate one possible cross-sectional shape that themembrane areas 68 and 69 can take. As in FIG. 10A, the membranestructures are tapered from their junctions with the central framemember 62 with which they are integrally formed.

Still referring to FIG. 8, the crescent-shaped membranous area 70 islocated at the inner surface of lower arcuate section 54. The lowerterminal point of this membrane region is located similarly to that ofthe opposed membrane area 69, being in a substantially proximal relationto the spring-hinge joint 57, whereas its upper terminal point islocated just about where the membranous area 69 crosses over arm 50below the mid-point of intersection 56.

The cross-section of the membrane area 70 can, as in the case ofmembrane areas 63, 64 illustrated in FIGS. 10 and 10A, take on a uniformthickness from a narrowed neck 71 junction with frame member 62 as inFIG. 12, or can have a tapered configuration as in FIG. 12A. Again, theprimary consideration is that the membranous structures are inwardlycompressible upon themselves so as not to interfere with the ability ofthe plastic body to flex and conformably engage the uterine walls inresponse to contractions.

An alternate embodiment having a different membranous configuration isillustrated in FIG. 14. As shown therein, the crescent-shaped membranousregion is greater in area than its counterpart in FIG. 8, as is alsotrue with the lower portion of membrane 69 extending from arcuate armsection 55. In addition, membrane region 70 extends upwardlysubstantially higher than in FIG. 8 to a point above the mid-point ofintersection 56, the purpose being to increase the total surface areaavailable for contact with the endometrium.

Due to their relative thinness and their locations, the membranousregions above described should not materially affect the flexibility ofthe plastic body or the ability of the frame to transmit contractionforces.

It should be evident that the foregoing description pertains to the mostlikely configuration of membranous regions, and variations therefrom toprovide increased surface area are within the scope of the invention solong as the flexibility and contractability of the device are notmaterially affected.

In accordance with a further aspect of the invention, pluralities ofsubstantially regularly distributed minute surface irregularities, orwhat can be called asperities 72, are preferably formed in the membranesurfaces front and back substantially across their entire extent. Theasperities provide an extremely slight controlled degree of irritationover the surface of the endometrium which should result in an increasedpresence of phagocytic cells in the uterine cavity and a consequentfurther reduction in the incidence of pregnancy.

The key features of these asperities are twofold and equally important.comprising other for First, they are minute in terms of height and widthas their dimensions are not likely to exceed fractions of a millimeterand,

Second, their profile must avoid any sharp, rough or jagged edges which,no matter how small, could possibly cause bleeding.

As long as these two criteria are met, the shape of the asperities canassume any number of basic designs such as circles, ridges and grids,stars, crosses, mounds or peaks and the like, as shown in FIG. 19.

In accordance with a further feature of the invention, the outer lobatewall bearing surfaces of the four arcuate sections of the forcetransmitting members are preferably formed at and adjacent thetransverse axes T-T and M-M with pluralities of low profileprotuberances 73 to create knurled gripping surfaces.

The knurl-forming protuberances have a dual purpose: to increase thestability of the device and prevent its migration in the uterine cavityand to enhance the ability of the frame to anchor against the uterinewalls in case of strong uterine contractions so that the device canbetter resist being pushed down toward the area of the internal os.

To illustrate and referring again to FIG. 5, under a bilateralcontraction at the level of the fundus, the device will transmit forcescontralaterally via its cross-bar mechanism causing the lower arcuatesections 54, 55 to expand outwardly against the uterine walls.Conversely, contractions at the level of the mid-uterus will compressarcuate segments 54 and 55 which, in turn, will cause the upper arcuatesections 52, 53 to expand outwardly and to anchor themselves in theupper portion of the cavity. To maximize their gripping ability, theknurl-forming protuberances are deployed at the four lateral lobateregions where contraction forces tend to exert most of their thrust.

The actuator contour of the protuberances 73 is not limited to anyparticular shape and, as is illustrated in FIGS. 15-18, they can beembodied in any number of suitable shapes. For example, rows of thinpliable fins of rounded contour extending from the frame 62 a fewmillimeters as shown in FIGS. l1, l2, and 12A can be employed, as can aseries of saw tooth notches or indentations in the frame itself as inFIGS. 16 and 18. Whatever their precise shape, it is important that theprotruberances 73 define a low profile having a substantially non-jaggededge to avoid injury without sacrificing gripping ability.

Recent clinical investigations of the use of metallic copper as anadjunct to intrauterine contraceptive devices have yielded promisingresults, although it is too early to pass any definite judgement on thelong term effects of copper on the endometrium.

In the event that such an adjunct is found to be desirable, a device inaccordance with the present invention would be wholly compatible withthe use of copper or any other metal, compound or bicomponent able toduplicate the anti-fertility mechanicm of copper which has yet to beprecisely determined. Should the ionic or electrical properties ofcopper be largely responsible for such mechanism, other metals couldconceivably include silver, gold or any other metal of low electricalresistivity.

The membrane surfaces of the device would provide a convenient carrierfor the metals which, if in wire form, can readily be stitched into thethin plastic membranes or, ifin ultra-thin plate form, can be tackedonto both surfaces of the membrane structure and interconnected. Still,among other possibilities, the entire device or parts thereof could becoated with a metallic film which would not affect its flexibility.

The device can be constructed from a wide variety of synthetic polymerresins such as polyethylene, polypropylene, nylon, polyester or teflonamong others, or any other suitable resilient material proven to benonallergenic and inert to human body tissue. Preferably, the materialshould have good molding properties and be suitable for injectionmolding-Although one single polymeric component is seen as preferablefor the device, a bicomponent can also be used such as an inner core ofpolyester coated with teflon or silicon or even an inner frame of metalsuch as stainless steel or a high molecular memory alloy such as nitinolcovered with a polymer. In any event, since the position of the devicein the uterine cavity may in some cases have to be checked, any of thewell-known radiopaque substances such as a barium sulphate can be addedto the resin.

As indicated, the device can be made by molding or G by any othersuitable forming process.

Referring to FIGS. 20-23, removal of the device from the uterine cavityis easily accomplished by the physician and with a minimum of discomfortfor the user, the key procedural step consisting of deactuating thespring-hinge joint 57. Referring specifically to FIG. 20, the physicianfirst pulls monofilament 60 connected to the apex of V joint 57 whichshould be adapted to be easily externally accessible through thecervical canal. With the lower arcuate sections 54 and 55 of the forcetransmitting members pressing against the walls of the uterine cavity, asufficient downward pull causes the lower arcuate sections to spreadapart and the expansion V joint 57 to pivot downwardly about its zonesof weakness 58 and 59. As soon as the V joint is inverted, the source ofspring energy to the force transmitting members 50 and 51 is deactuatedand the force transmitting members offer a minimum resistance to furtherpulling.

Channelled by the narrowing walls of the uterinecavity, further downwardforce exerted on the filament causes the joint 57 to elongate (FIG. 21)and, in turn, forces the collapse of the entire bottom section of thedevice whereby the lower arcuate arm sections 54, 55 are forced toassume a parallel arrangement with respect to longitudinal axis SS. Theelongated shape and rounded contour taken by the V joint is quiteimportant in that it progressively opens the cervical canal and dilatesit to facilitate the outward passage of the device.

In the following FIGS. 22 and 23, the force transmitting members 50, 51along their entire extent are shown reduced to a fully parallelarrangement, thus presenting a minimum of surface resistance to theirintroduction in and passage through the cervical canal.

As has already been stated above, the procedure and means for insertingthe contraceptive device into the uterus must insure against perforationof the uterine wall. In addition, the introduction of the device shouldbe a painless procedure and one which is easy and relatively fast toaccomplish even by paramedical personnel after only a brief period oforientation and training. In accordance with a further aspect of theinvention, an introducer implement is provided which meets theserequirements and which constitutes a major departure from theprevalently used cannulae or tubes, although the latter can be used ifso desired.

Referring to FIGS. 24 and 25, the introducer comprises a cylindricalshaft 74 of bilogically inert and relatively stiff material having acurvilinear profile with a handle 75 formed in one end and meanscomprisin a rectilinear shaft section 76 formed in the othe end ofreleasably holding a contraceptive device 77 of the type hereinillustrated and described in proper orientation and contracted conditionfor passage into the uterine cavity.

The handle illustratively comprises a flattened section of the shaft atthe end preferably having a knurled surface 78 to facilitate gripping.As illustrated in FIG. 26, the handle is designed to be held by the userbetween thumb and index finger and can be suitably contoured with awidened area at its junction with the bowed portion of the shaft, asshown, to maximize surface contact with the thumb to facilitate controland manipulation of the implement during insertion.

An important feature of the introducer resides in its curvilinearprofile illustrated in FIGS. 24 and 26. As shown, the shaft 74 describesa curve which angles downwardly from its end having the handle 75 to anintermediate point on the shaft where it reverses its direction ofcurvature. The effect created by this double reverse curvature of theshaft is that the rectilinear section of the shaft 76 holding thecontraceptive device extends in axially offset substantially parallelrelation with the handle 75 of the implement.

As can best be seen in FIG. 26, the curvature of the shaft in the regionof the device holding section 76 conforms to the general angulation ofthe longitudinal section of the uterine cavity when the patient isproperly positioned on the examining table, while the reverse curvatureat the opposite end near the handle 75 should be such as to prevent thefingers from interfering with the physicians line of vision and also topermit the forward end of the introducer to be lowered in a way that theobstacle of the perineum is overcome.

Referring again to FIG. 24, the angle [3 formed between the axis of therectilinear section 76 of the shaft and the tangent to the shaft drawnfrom the handle extremity at the opposite end should be substantiallysimilar to the angle 6 formed between the horizontal and the tangent tothe shaft drawn from the forward extremity of the shaft. Both anglesshould preferably range between about and primarily to conform to theangulation of the uterine cavity.

Both angles being equal or substantially equal permits the forwardforces exerted on the shaft at the handle end by the user to betransmitted on a parallel plane to the forward end of the shaft holdingthe device with little or no loss of force. This provides greatersensitivity to the hand and better judgement as to the amount of forceto be applied, which is particularly important in cases of unrecognizedretroflexed uteri assuring greater safety against perforation.

Another important feature of the invention assuring against perforationof the fundus are the groups of thin annular bands 79, 80 and 81 formedon the shaft which provide a means fo gauging the depth reached by theforward end of the introducer in the uterus. The three reference levelscan for illustration be spaced one centimeter apart representing the 5,6 and 7 centimeter marks measured from the tip of the forward end 76.

As can be seen, the first or 5 centimeter reference leve 79 isrepresented by a single band, the second or 6 centimeter level 80 by twospaced apart bands and the third or 7 centimeter level 81 by anarrangement of three bands. These illustrative dimensions have beenempirically determined and should cover the full range of uterine depthsfrom the external cervical os to the fundus. The sequential groups ofbands where each succeeding group has an additional band is judgedpreferable over numbers imprinted on the introducer which are sometimesused but difficult to decipher during insertion of the device.

Preferably, the bands are in a color providing a sharp contrast with thecolor of the shaft and readily distinguishable from the colorenvironment of the vaginal walls. By way of example, bright greencolored bands on a white introducer shaft should provide the contrastdesired.

A final safeguard against perforation of the fundus are the flanges 82preferably formed on the shaft 8 centimeters from the tip of the forwardend 76. Flanges 82 prevent the introducer from being pushed into theuterus any deeper, although a uterine cavity of such depth is ratherrare.

The introducer shaft 74 is preferably circular in cross-sectionintermediate its ends and is formed with segments 83 and 84 of differentdiameter for reasons of structural strength. Segment 83 which extendsfrom the rectilinear section of the shaft 76 to the flanges 82 canillustratively have a diameter in the order of4 millimeters. Segment 84,which illustratively can be 5 millimeters in diameter, extends fromflanges 82 to the junction with handle 75. This stepped increase indiameter is intended to provide sufficient strength in the major portionof the shaft to withstand the force necessary for the introduction ofthe device and at the same time to provide a certain degree of desiredflexibility in the similar portion of th shaft in the region to beinserted.

Illustrative of suitable overall shaft dimensions are the following:

x z 1.7 cm. y z 7.5 cm. 2 z 26 cm.

In accordance with the invention, reference being had to FIGS. 29-31 inparticular, the means for releasably holding the contraceptive device 77comprises a cavity formed in the rectilinear shaft section 76 having asubstantially flat back support wall 85, and two end Walls 86 and 87,the cavity being open on the sides. As can readily be seen, the lengthand profile of the cavity are contoured to conform to the shape of thedevice 77 when held in contracted condition for insertion, the back wallhaving a recessed area 88 substantially midway between end walls 86, 87to accommodate the double thickness of the overlapped force transmittingarms 50, 51 to avoid any potentially harmful protrusion.

In accordance with the invention, locating pin means operativelyassociated with the cavity is provided for cooperating with the pinengaging openings formed in the device 77 to releasably position thedevice for insertion. In the illustrative embodiment of FIGS. 29-31, twolocating pins 89 and 90 depend substantially perpendicularly from backwall into the cavity. Pins 89 and are situated on the axis of the shaftand are spaced apart, as shown, to cooperate with the pin engagingopenings 65 and 66 of the upper arms of the device 77 and with the pinengaging opening in ring 61 at the apex of joint 57 in the lower portionof the device.

As is clearly shown in FIG. 31, the devic 77 is releasably mounted onthe introducer in a contracted condition with its normally movable forcetransmitting members 59 and 51 held in fixed relation and itslongitudinal axis S--S parallel to the axis of the shaft 74. The rearlocating pin 89 is disposed within and extends through the ring 61thereby releasably engaging the lower end of the device. The upper endof the device is similarly releasably engaged by forward locating pin 90which is disposed within and extends through the openings formed in theupper membrane regions 63 and 64, the upper arcuate sections of arms 50and 51 being contracted so that the membrane regions 63 and 64 areoverlapped with their pin engaging openings superimposed.

Preferably, the locating pins 89 and 90 are axially spaced apart so thatthe device when thus engaged is also compressed along its longitudinalaxis SS, the overall length of the compressed device being reduced by afew millimeters from its unstressed dimension. As will hereinafterbecome apparent, this constitutes an important safety factor againstfundal perforation.

In the embodiment of FIGS. 2931, the locating pins 89 and 90 aredesigned to have a force fit engagement with their cooperating pinengaging openings in the device 77. As can be seen, each pin is shapedwith a rounded enlarged terminus and a tapered stem.

An additional feature of the introducer is the bulbous searching head 91formed in the forward or leading end of the shaft. Extending out frontof the leading edges of the device 77 by a few millimeters, it performsduring insertion the triple function of dilating the narrow lumen of thecervical canal, of deflecting some of the stress exerted onto theleading edges of the device and, most importantly, of serving as a guideto the physician in the initial'portion of the cervical canal which islined with the glandular cavities of the arbor vitae (See FIG. 26). Ifthe forward tip of the introducer were too sharp, one of these cavitiescould be mistaken for the cervical canal leading to possible uterineperforation.

Illustrated in FIGS. 32-34 is an introducer having an alternateconfiguration in accordance with the invention, FIG. 45 illustratingalternate membrane opening locations suitable for use therewith. Asshown, the in- Y troducer of FIG. 32 differs from that of FIG. 29 in tworespects.

In order to minimize the length of the implement, the searching head 92while retaining a bulbous configuration is modified so that the forwardend of the contracted contraceptive device 77 is exposed, the cavityformed in the shaft 74 having only a rear end wall 87 and no front endwall. To compensate for the increased stress exerted on the leadingedges of the arcuate arms of the device, the pin engaging openings 65and 66 in the membrane regions 63 and 64 are located at the junctions ofthe membranes with the frame 62 as shown in FIG. 45. Engagement with thelocating pin 93, illustratively having a modified shape from thecorresponding pin 90 of FIG. 29, thus occurs at the very edge of thestructural frame 62 imparting greater strength and resistance todistortion than would be the case if the opening locations were as shownin FIG. 31.

It should, of course, be understood that the locating pins can have avariety of force fit shapes such as shown in FIGS. 35 and 36, and canhave a hook or clamp configuration such as shown in FIG. 37 and embodiedin the introducer of FIGS. 38-40. The introducer shown in FIGS. 38-40,adapted for use with a membrane opening configuration such as in FIG.45, constitutes still another possible variation to that of FIGS. 29-31within the scope of the invention.

As best illustrated in FIG. 38, there is provided a bulbous searchinghead 94 having a forward contour substantially similar to that of head91 of FIG. 29. As contradistinguished from the embodiment of FIG. 32,the cavity formed in the linear section 76 of the shaft of FIG. 38 hasboth a rear end wall 87 and a forward end wall 95 formed by thesearching head 94. The locating pin means for releasably engaging thecontraceptive device comprises a pair of mirror-image hook shaped rearlocating pins 96 and 97 cooperating to form a spring-like two prongclamp, and a forward hook shaped locating pin 98 similarly cooperatingwith the searching head 94 which can be seen to have a hooklikeconfiguration as well.

Yet another introducer embodying the principles of the invention isillustrated in FIGS. 41-44. This type of introducer differs markedlyfrom the other three embodiments herein disclosed. As illustrated, thelinear section 76 is formed with a pair of cavities on opposite sides ofthe shaft. The lower cavity having a substantially flat rear supportwall 99 and two end walls 100 and 101 differs from the similarly locatedcavities of the other illustrative embodiments in that it is shallowerand does not have a recessed area designated 88 in FIGS. 29, 32 and 38.The upper cavity, which is substantially of the same depth butsubstantially shorter in length than the lower cavity, has a flat rearwall 102 and two end walls 103 and 104.

The lower cavity has locating pin means 105 and 106 depending from rearwall 99, pin means 106 comprising three locating pins in the nature of atriple prong clamp, as shown. The upper cavity has a single locating pin107 substantially coaxially aligned with pin of the lower cavity. As canbe seen, the searching head 108 has a bulbous contour similar to thecontour of head 91 of the embodiment of FIG. 29.

The contraceptive device 77 is affixed to the introducer in a mannerdifferent from that previously described. The device is mounted with itsforce transmitting members 50 and 51 disposed in different planes,member 50 being disposed in the lower cavity and engaged by locating pin105 and member 51 beingbent around the shaft and disposed in the uppercavity engaging locating pin 107. The ring 61 located at the lower axialend of the device is disposed in the lower cavity in the same plane asmember 50 and is held by pin means 106.

It is preferred that the device and introducer be sold fully assembledand prepackaged in a sterilized condition. Referring to FIG. 46, thepackage can comprise a transparent heat-sealable plastic casing 109 ofrectangular configuration and having a removable cardboard base 110.Illustratively, the base is provided with two rows of perforationsrunning along its entire length. One end of the base can be made toextend beyond the edge of the enclosure to provide a pull tab. With sucha construction, the base can be readily removed providing access to thecontents.

Although the foregoing implies that the device is mounted in itscontracted condition on the introducer ready for insertion,alternatively the device may come attached only via its lower ring 61with the upper arcuate arms in their relaxed extended position. This maybe desirable in the event that a synthetic resin of low resilience andweak molecular memory is used to injection-mold the device. In suchcase, the physician need only bend the upper arcuate arm sections of thedevice so that their membrane openings superimpose and then snap themonto the forward locating pin of the introducer. Of course, sterilegloves will be used during as sembly.

Insertion of the device is relatively simple. Referring back to FIG. 26,the bulbous forward end of the introducer shaft is gently inserted intothe cerival os with the device disposed downwardly and is slowlyadvanced through the cervical canal until a definite snap is feltthrough the introducer shaft. This snap occurs shortly after the device,constricted. during passage through the narrow cervical canal, haspassed through the constrictive ring formed by the internal os where itexpands back to its normal contracted condition as mounted on theintroducer. At this point, the device is ready to be released.

It should be apparent that by virtue of its pliability the device uponentering the narrow cervical canal can be simultaneously squeezedinwardly and elongated reducing its resistance and permitting easyinsertion. In the event that any partially inserted device has to bewithdrawn, the locating pins are such that the device will remainattached to the introducer and, therefore, safely retrievable eventhough resistance is met by the lower edges of the device.

The release technique can best be understood by reference to FIGS. 27and 28. In its normal state, the uterine cavity has the form of a fiat,collapsed envelope. When an object is introduced therein, the muscularlayers will give" but will nevertheless stay in close contact with theobject due to their tight elasticity.

Thus, the uterine walls exert a certain amount of pressure onto thesurface of the device shown ready for release in FIG. 27 preventing itfrom being rotated about its longitudinal axis which extendsperpendicularly to theplane of FIG. 27.

To release the device, the introducer is rotated until the force exertedby the uterine walls on the device causes the locating pins to disengagetheir cooperating pin engaging openings. Thus disengaged, thespringhinge joint 57 causes the force transmitting members of the deviceto spring back to their normal extended configuration represented inFIG. 28. As shown in FIG. 28, the device is held in close contact by thesurfaces of the endometrium 112 without contacting the extreme lateralends of the cavity.

The relative position of the searching head 91 with respect to thefundus at the point of release is illustrated in FIG. 26. Since theoverall length of the device is 25 millimeters for parous (20millimeters for nulliparous), the total extent of the introducer engagedin the uterus will very rarely exceed 60 millimeters in par ous and 55millimeters in nulli-parous Women. These depth levels are at leastmillimeters below the normal level of the fundus so that there is nofundal contact during insertion. This represents a major safety factorassuring in conjunction with the bulbous search ing head and depthcontrol bands on the shaft that fundal perforation will not occur.

The relationships between the various physical features of the deviceembodying the present invention and the four major uterine physiologicaleffects mentioned earlier can be summarized in tabular form where a plussign indicates an increase as a function of a physical factor, a minussign a decrease and a zero, no significant change.

Physiological Effects Physical Features Bleeding Pregnancy Thus, basedon theoretical considerations, reduction in pregnancy rate in thepresent device is seen to be primarily due to the irritation generatedby the membrane surfaces and their minute asperities while the size ofthe device and the knurled lobate regions can be regarded as ancillaryfactors since both features essentially contribute to keeping the devicein the strategic implantation ground of the middle portion of theuterine cavity. And whereas the size, shape, cross-bar mechanism andlobate regions of the device should result in a measurably lowerexpulsion rate than has previously been attainable, these physicalelements are also seen for the most part to reduce pain and bleeding, orat worst to cause no significant change, since they are designed toconform to the uterine physiology.

What is claimed is:

1. An intrauterine contraceptive device comprising a substantiallymembranous readily deformable and inwardly contractible but resilientplanar body having an outer substantially lobate contour including upperand lower pairs of resilient, structural uterine wall bearing lobeslaterally disposed in substantial mirror-image relation with respect toa common symmetrical axis extending longitudinally therebetween when inunstressed condition, said planar body further comprising a pair ofdiagonally extending crossed structural force transmitting membersoperatively interconnecting in direct force transmitting relationdiagonally opposed lobes of said upper and lower lobe pairs wherebyforces exerted on said lobes by said uterine walls are contralaterallytransmitted and diffused through said body and inward compression of alobate region by uterine wall forces being thereon causes the diagonallyassociated lobate region to exert increased outward pressure on saiduterine wall.

2. An intrauterine contraceptive device capable of being readilycompressed for passage into the uterine cavity and, when released, ofexpanding to conformably engage the uterine walls to resist expulsion,said device comprising a substantially planar, readily deforrnable,pliable but resilient body of a resilient substantially filamentaryframe having an outer substantially lobate contour including upper andlower pairs of resilient, structural uterine wall bearing lobeslaterally, outwardly disposed in mirror-image relation defining a commonlongitudinal axis of symmetry when in unstressed condition, said devicebeing adapted by location within said uterine cavity such that said axisis substantially aligned with the cervical canal, said filamentary frameof said body also having a pair of resilient, structural forcetransmitting members diagonally extending in crossed relation acrosssaid axis operatively interconnecting in force transmitting relationdiagonally opposed lobes of said upper and lower pairs, said forcetransmitting members being independently freely rotationally andtranslationally movable relative to each other, said upper and lowerstructural lobes and said pair of structural force transmitting membersdefining a configuration having two free ends and being continuouslytraceable between said two ends, whereby forces exerted on said lobes bysaid uterine walls are contralaterally transmitted and diffused throughsaid body and inward compression of any one of said four lobate regionsby uterine wall forces bearing thereon causes the diagonally associatedlobate region to exert increased outward pressure on said uterine wall,said resilient body further comprising membrane means operativelyassociated with said frame providing substantial surface area forcontact with the endometrium when said device is positioned within saiduterine cavity.

3. A device as defined in claim 2, said membrane means formingmembranous surfaces having asperities substantially regularlydistributed thereon.

4. An interauterine contraceptive device capable of being readilycompressed for passage into the uterine cavity and, when released, ofexpanding to conformably engage the uterine walls to resist expulsion,said device comprising a substantially planar readily deformable pliablebut resilient body having an outer substantially lobate contourincluding upper and lower pairs of resilient, structural uterine wallbearing lobes laterally, outwardly disposed in mirror-image relationdefining a common longitudinal axis of symmetry when in unstressedcondition, said device being adapted for location within said uterinecavity such that said axis is substantially aligned with the cervicalcanal, said resilient body further comprising a pair of resilient,struc-

1. An intrauterine contraceptive device comprising a substantiallymembranous readily deformable and inwardly contractible but resilientplanar body having an outer substantially lobate contour including upperand lower pairs of resilient, structural uterine wall bearing lobeslaterally disposed in substantial mirror-image relation with respect toa common symmetrical axis extending longitudinally therebetween when inunstressed condition, said planar body further comprising a pair ofdiagonally extending crossed structural force transmitting membersoperatively interconnecting in direct force transmitting relationdiagonally opposed lobes of said upper and lower lobe pairs wherebyforces exerted on said lobes by said uterine walls are contralaterallytransmitted and diffused through said body and inward compression of alobate region by uterine wall forces being thereon causes the diagonallyassociated lobate region to exert increased outward pressure on saiduterine wall.
 2. An intrauterine contraceptive device capable of beingreadily compressed for passage into the uterine cavity and, whenreleased, of expanding to conformably engage the uterine walls to resistexpulsion, said device compriSing a substantially planar, readilydeformable, pliable but resilient body of a resilient substantiallyfilamentary frame having an outer substantially lobate contour includingupper and lower pairs of resilient, structural uterine wall bearinglobes laterally, outwardly disposed in mirror-image relation defining acommon longitudinal axis of symmetry when in unstressed condition, saiddevice being adapted by location within said uterine cavity such thatsaid axis is substantially aligned with the cervical canal, saidfilamentary frame of said body also having a pair of resilient,structural force transmitting members diagonally extending in crossedrelation across said axis operatively interconnecting in forcetransmitting relation diagonally opposed lobes of said upper and lowerpairs, said force transmitting members being independently freelyrotationally and translationally movable relative to each other, saidupper and lower structural lobes and said pair of structural forcetransmitting members defining a configuration having two free ends andbeing continuously traceable between said two ends, whereby forcesexerted on said lobes by said uterine walls are contralaterallytransmitted and diffused through said body and inward compression of anyone of said four lobate regions by uterine wall forces bearing thereoncauses the diagonally associated lobate region to exert increasedoutward pressure on said uterine wall, said resilient body furthercomprising membrane means operatively associated with said frameproviding substantial surface area for contact with the endometrium whensaid device is positioned within said uterine cavity.
 3. A device asdefined in claim 2, said membrane means forming membranous surfaceshaving asperities substantially regularly distributed thereon.
 4. Aninterauterine contraceptive device capable of being readily compressedfor passage into the uterine cavity and, when released, of expanding toconformably engage the uterine walls to resist expulsion, said devicecomprising a substantially planar readily deformable pliable butresilient body having an outer substantially lobate contour includingupper and lower pairs of resilient, structural uterine wall bearinglobes laterally, outwardly disposed in mirror-image relation defining acommon longitudinal axis of symmetry when in unstressed condition, saiddevice being adapted for location within said uterine cavity such thatsaid axis is substantially aligned with the cervical canal, saidresilient body further comprising a pair of resilient, structural forcetransmitting members diagonally extending in crossed relation acrosssaid axis operatively interconnecting in force transmitting relationdiagonally opposed lobes of said upper and lower pairs, said forcetransmitting members being independently freely rotationally andtranslationally movable relative to each other, said upper and lowerstructural lobes and said pairs of structural force transmitting membersdefining a configuration having two free ends and being continuouslytraceable between said two ends, whereby forces exerted on said lobes bysaid uterine walls are contralaterally transmitted and diffused throughsaid body and inward compression of any one of said four lobate regionsby uterine wall forces bearing thereon causes the diagonally associatedlobate region to exert increased outward pressure on said uterine wall,and knurl forming means disposed on the outer wall bearing surfaces ofsaid lobes for gripping the uterine wall to provide stability andresistance to downward displacement of the device.
 5. An intrauterinecontraceptive device capable of being readily compressed for passageinto the uterine cavity and, when released, of expanding to conformablyengage the uterine walls to resist expulsion, and thereafter of beingreadily contracted for removal, said device comprising two substantiallysimilar resilient S-shaped force transmitting members having respectiveupper and lower arcuate sections, said members in unsTressed conditionsbeing arranged in substantially planar overlapped mirror-image relationwith their said upper and lower arcuate sections outwardly disposed withrespect to a symmetrical axis extending longitudinally therebetween,said device being adapted for location within said uterine cavity withsaid axis substantially aligned with the cervical canal and said upperand lower arcuate sections forming lateral uterine wall bearing lobes,said device further comprising spring-hinge means normally resilientlyjoining the terminal portions of said lower arcuate sections andmanually operable withdrawal means operatively associated therewith fordeactuating the resilient forces of said hinge means to permit saidforce transmitting members to be non-resiliently readily contractedtowards said longitudinal axis for removal of the device, said upperarcuate sections of said members terminating in free ends, and saidspring-hinge means comprising a substantially filamentary extension ofsaid force transmitting members forming an inverted-V expansion jointhaving an apex substantially coincident with said longitudinal axis. 6.A device as defined in claim 5, said withdrawal means comprising zonesof weakness formed in said force transmitting members at their junctionswith the base of said inverted-V joint and means for inverting saidjoint, said means comprising filament means connected to said apex ofsaid joint and adapted to be readily externally accessible for exertinga downward force thereon.
 7. An intrauterine contraceptive devicecapable of being readily compressed for passage into the uterine cavityand, when released, of expanding to conformably engage the uterine wallsto resist expulsion, and thereafter of being readily contracted forremoval, said device comprising two substantially similar resilientS-shaped force transmitting members having respective upper and lowerarcuate sections, said members in unstressed condition being arranged insubstantially planar overlapped mirror-image relation with their saidupper and lower arcuate sections outwardly disposed with respect to asymmetrical axis extending longitudinally therebetween, said devicebeing adapted for location within said uterine cavity with said axissubstantially aligned with the cervical canal and said upper and lowerarcuate sections forming lateral uterine wall bearing lobes, said devicefurther comprising spring-hinge means normally resiliently joining theterminal portions of said lower arcuate sections and manually operablewithdrawal means operatively associated therewith for deactuating theresilient forces of said hinge means to permit said force transmittingmembers to be non-resiliently readily contracted towards saidlongitudinal axis for removal of the device, aid upper arcuate sectionsof said members terminating in free ends, and membrane means secured tosaid force transmitting members providing substantial surface area forfrictional contact with the endometrium when said device is positionedwithin said uterine cavity.
 8. A device as defined in claim 7, saidmembrane means forming membranous surfaces having asperitiessubstantially regularly distributed thereon.
 9. A device as defined inclaim 7, said membrane means comprising a membranous region secured tothe lower terminal portion of each of said upper arcuate sections ofsaid force transmitting members.
 10. A device as defined in claim 7,said membrane means comprising a membranous region operativelyassociated with said force transmitting members at their area ofoverlap.
 11. A device as defined in claim 7, said membrane meanscomprising a membranous region secured to each of said lower arcuatesections of said force transmitting members.
 12. An intrauterinecontraceptive device capable of being readily compressed for passageinto the uterine cavity and, when released, of expanding to conformablyengage the uterine walls to resist expulsion, and thereafter of beingreadily contracted for removal, Said device comprising two substantiallysimilar resilient S-shaped force transmitting members having respectiveupper and lower arcuate sections, said members in unstressed conditionbeing arranged in substantially planar overlapped mirror-image relationwith their said upper and lower arcuate sections outwardly disposed withrespect to a symmetrical axis extending longitudinally therebetween,said device being adapted for location within said uterine cavity withsaid axis substantially aligned with the cervical canal and said upperand lower arcuate sections forming lateral uterine wall bearing lobes,said device further comprising spring-hinge means normally resilientlyjoining the terminal portions of said lower arcuate sections andmanually operable withdrawal means operatively associated therewith fordeactuating the resilient forces of said hinge means to permit saidforce transmitting members to be non-resiliently readily contractedtowards said longitudinal axis for removal of the device, said upperarcuate sections of said members terminating in free ends, and knurlforming means disposed on the outer wall lobe bearing surfaces of saidarcuate sections of said force transmitting members for gripping theuterine wall to provide stability and resistance to downwarddisplacement of the device.
 13. An intrauterine contraceptive devicecapable of being readily compressed for passage into the uterine cavityand, when released, of expanding to conformably engage the uterine wallsto resist expulsion, and thereafter of being readily contracted forremoval, said device comprising two substantially similar resilientS-shaped force transmitting members having respective upper and lowerarcuate sections, said members in unstressed condition being arranged insubstantially planar overlapped mirror-image relation with their upperand lower arcuate sections outwardly disposed with respect to asymmetrical axis extending longitudinally therebetween and wherein theoverall unstressed transverse extent of said device between said pair ofupper arcuate sections is substantially greater than between said pairof lower arcuate sections, and said force transmitting members overlapone another substantially mid-way along said longitudinal axis andextend thereat in relation to one another at an angle within the rangeof about 0* to 30*, said device being adapted for location within saiduterine cavity with said axis substantially aligned with the cervicalcanal and said upper and lower arcuate sections forming lateral uterinewall bearing lobes, said device further comprising spring-hinge meansnormally resiliently joining the terminal portions of said lower arcuatesections and manually operable withdrawal means operatively associatedtherewith for deactuating the resilient forces of said hinge means topermit said force transmitting members to be non-resiliently readilycontracted towards said longitudinal axis for removal of the device,said upper arcuate sections of said members terminating in free ends,said device having an overall dimension such that when in positionwithin the uterus, its lower extremity is at a level substantially abovethe average level of the internal os and its lateral extremities aresubstantially spaced apart from the extreme lateral ends of said uterinecavity.
 14. In an intrauterine contraceptive device having alongitudinal axis substantially aligned with the cervical canal whensaid device is properly positioned in the uterus and having twosubstantially filamentary arms normally substantially symmetricallydisposed with respect to said axis in movable spaced apart relation andextending upwardly away from the cervical canal, spring-hinge meansjoining the terminal portions of said arms nearest said cervical canalwhen said device is properly positioned in the uterus resilientlyresisting inward contraction of said arms towards said axis, andwithdrawal means operatively associated with said spring-hinge means fordeactuatiNg the resilient forces of said hinge means to permit said armsto be non-resiliently readily inwardly contracted towards saidlongitudinal axis for removal of the device, said spring-hinge meanscomprising a substantially filamentary extension of said arms forming aninverted-V expansion joint having an apex substantially coincident withsaid longitudinal axis and displaced with respect to the lowermostextremities of said arms upwardly away from said cervical canal whensaid device is properly positioned in the uterus, said withdrawal meanscomprising zones of weakness formed in said arms at their junctions withthe base of said inverted-V joint and filament means affixed to saidapex for inverting said joint upon exertion of a downward force thereon,said filament means being adapted to be readily externally accessiblethrough the cervical canal.
 15. In a device as defined in claim 14, saidinverted-V joint having a substantially rounded contour at its apexserving as a means for dilating the cervical canal during removal ofsaid device.
 16. In an intrauterine contraceptive device having alongitudinal axis substantially aligned with the cervical canal whensaid device is properly positioned in the uterus and having twosubstantially filamentary arms normally substantially symmetricallydisposed with respect to said axis in movable spaced apart relation andextending upwardly away from the cervical canal, spring-hinge meansjoining the terminal portions of said arms nearest said cervical canalwhen said device is properly positioned in the uterus resilientlyresisting inward contraction of said arms towards said axis, saidspring-hinge means comprising a filamentary extension of said armsforming a reversible inverted-V expansion joint having an apexsubstantially coincident with said longitudinal axis and displaced withrespect to the lowermost extremities of said arms upwardly away fromsaid cervical canal when said device is properly positioned in theuterus, means accessible externally of the uterus for inverting saidinverted-V joint so that its said apex is substantially coincident withsaid longitudinal axis and displaced with respect to the lowermostextremities of said arms downwardly towards said cervical canal, saidjoint having a substantially rounder contour at its said apex wheninverted whereby said joint serves to dilate the cervical canal duringremoval of said device.